Okay, before you lose your shit, let's explain this. No, this can't currently play commercial 3DS games, and most likely won't (for a long time at least). It's really only useful for developers, but it's pretty cool. More info below.
bunnei
Hey guys… I'd like to share a project that I've been working on with a few others for the past few months – the first public project to attempt 3DS emulation. "Citra" (https://github.com/bunnei/citra/) is an experimental Nintendo 3DS emulator/debugger written in C++ (and licensed under GPLv2).
At this time, it is in the very initial stages of development, and is only capable of running homebrew. It currently supports: • ARM9/ARM11 interpreter for the 3DS "appcore" – the processor core dedicated to running user applications • (Some) OS HLE to support userland interaction with the various 3DS OS services • Loading of ELF and launcher.dat files • Framebuffer rendering • Debugger with ARM11 disassembler, register view, callstack and symbol loading (written in Qt) • Supported on both Linux and Windows (MS Visual Studio 2013 Express)
I want to emphasize that for the long-term, this project will only (potentially) be useful to developers – there are many non-existent components that are absolutely essential to even loading a commercial game (and furthermore there is no gamepad or hardware 3D support, among many many other things).